Following another steep sell-off Thursday, stocks appeared calmer — for now — and posted strong gains Friday.

The Dow was up 650 points, or 1.64%, in afternoon trading. The S&P 500 rose 1.7% and the Nasdaq was 1.9% higher. Markets were buoyed by Boston Fed President Susan Collins telling the Friday that the Fed would step in to support financial markets if there were signs of distress.

But stock market investors have been trading on a knife’s edge, and any announcement coming from the Trump administration on tariffs has the ability to send stocks surging or tumbling. For example, stocks plunged Thursday after the Trump administration clarified the math it had already used to set China’s massive 145% tariff. The street had believed the tariff was 125%. The Dow sank sharply, at one point falling more than 2,000 points.

Meanwhile, gold prices surged above a record high $3,200 a troy ounce on Friday. Gold is up more than 21% this year and just posted its best quarter since 1986. The yellow metal is considered a safe haven amid economic and political uncertainty.